1. Field of the Invention
The present application generally relates to injections, and more specifically relates to medical devices for administering multiple injections.
2. Description of the Related Art
Many patients are required to receive injections whereby the injected substance includes two or more components. In many instances, the two or more components must be stored separate from one another, but are mixed together immediately prior to injecting the combined components into a tissue. For example, diabetic patients often receive injections having two different components that must be separated prior to injection. More specifically, it is known that fibrinogen and thrombin may be injected to form a fibrin polymer in-situ so as to induce angiogenesis. Due to the fact that fibrinogen and thrombin will rapidly polymerize upon interaction, it is critical that the two components be maintained apart from one another until applied at the application site.
Providing injections having two or more components are further complicated by the fact that the dosage requirements vary from patient to patient, or even for the same patient. Attempts to combine the separate components into a final, injectable solution often result in contamination of one or more of the individual components. In addition, attempts to address the administration of two or more medications in liquid form may require administering multiple injections into a patient in order to reach the recommended dose, a first injection for the first component and simultaneously a second injection for the second component. Administering multiple injections every time an injection is required is time consuming, may result in improper mixing of components, and may cause tissue damage.
A number of devices have been developed for maintaining at least two substances apart from one another before being injected. For example, U.S. Pat. No. 4,359,049 to Redl et al. teaches a device that holds two syringes together in a support having a common actuator. The dispensing end of each of the syringes is inserted into a collection manifold where the two separate substances are mixed together. The mixed substances are then dispensed through a common needle inserted into an application site.
U.S. Pat. No. 4,609,371 to Pizzino discloses a device including a dual syringe that provides for the simultaneous or sequential injection of two different injectable liquids. The dual syringe includes two barrels, each having a plunger for the injection of a liquid, and a manually operable three-position rotary valve that controls the filling of the syringe and the outflow of the liquid from the syringe. The valve has three different positions for enabling the liquid to be dispensed either from the first barrel only, the second barrel only, or both barrels simultaneously.
Commonly assigned EP 1 845 860, the disclosure of which is hereby incorporated by reference herein, teaches an applicator device for applying a multi-component fluid, especially a multi-component tissue glue, including a plurality of substantially cylindrical supply containers for respectively one component of the fluid to be applied. Each supply container has a front end with an out-let opening, a rear end opposite to the front end, and a slidably displaceable piston arranged within the supply container and having a piston rod extending out of the rear end for operating the piston. The applicator device includes a manifold having terminal ends with a first port for fluid connection with the front ends of the supply containers. The manifold also has internal channels extending from the first ports of the terminal ends to an outlet site. The applicator device includes a holding element for holding the supply containers, and a coupling element extending from the holding element and having a connection end connected to the manifold, whereby the connection end of the coupling element is bonded to the manifold.
Other attempts to provide injectors that mix two substances include devices that provide two hollow injection needles that are bonded together side-by-side. The relatively large thickness of the composite needle provides an enlarged distal aperture that may damage tissue upon insertion. In addition, adequate mixing of the two individual components is not guaranteed because the components emerge laterally, side-by-side from the distal end of the injection needles.
WO0069488A2 discloses an injector device for containers with an opening for an injection needle. The injector includes a housing, a seat or a carrier arranged to hold the needle and for allowing movement thereof in relation to the housing between a rear, needle-covering, position and a forward, needle exposing position. The injector has a penetration arrangement operable to move the needle from the rear position to the forward position, a return arrangement to move the needle in the rearward direction, and an injection arrangement to expel container content through the needle. The injector has a control button arranged on the housing that triggers the penetration arrangement and injection arrangement.
U.S. Pat. No. 4,026,288 discloses a syringe injecting device having a body with a slideway therein that receives a syringe carriage biased into one position by a spring and reciprocal in the slideway. A handle extends from the body and there is a communication between the carriage for the syringe and a gear in the handle. The gear is controlled by a latch having a detent which may be released by a trigger from permitting the carriage to be impelled forward under spring action to insert the needle of the syringe into a body.
In spite of the above advances, there remains a need for an applicator device that provides for the efficient administration of multiple and sequential injections of a substance including at least two components. There also remains a need for an applicator device for administering injections that enables a single puncture of a patient's skin to properly inject the two or more components that are mixed together. There is also a need for an applicator device that enables medical personnel to cover a broad area of tissue using multiple and sequential injections. In addition, there remains a need for an applicator device that may be easily re-filled with additional quantities of the two or more components. Moreover, there remains a need for an applicator device that is relatively inexpensive to manufacture, safe, and easy to use. There also remains a need for an applicator device having an injection needle that may be automatically extracted from the patient's skin without the need for the administrator to lift the device upward from the injected surface so that the device allows for multiple injections on a 2-D surface of a tissue while moving the device.